1. Field of the Invention
The present invention relates to an ignition system for an automobile engine.
2. Description of the Prior Art
A conventional multi-ignition system supplies ignition currents to the ignition plug many times in response to an ignition timing signal. This prevents the ignition from misfire. This kind of multi-ignition system uses an ignition coil. In order to obtain a high ignition energy, a time to charge the primary winding of the coil requires a fairly long period of time. Spark break which is a time period between two sparks becomes longer because of a longer charging time of the ignition coil. Spark break can be reduced by using an ignition coil with a less inductance. This, however, reduces the ignition energy of the spark. Japanese Patent Laid Open Hei 1-16281 (1989) shows an ignition system using a DC-DC converter. A DC-DC converter converts a power voltage into a higher voltage to charge the primary coil quickly. A DC-DC converter, however, makes a system fairly big and a higher voltage applied to the primary coil may make a secondary coil's life shorten.